31,744 research outputs found
Formal change impact analyses for emulated control software
Processor emulators are a software tool for allowing legacy computer programs to be executed on a modern processor. In the past emulators have been used in trivial applications such as maintenance of video games. Now, however, processor emulation is being applied to safety-critical control systems, including military avionics. These applications demand utmost guarantees of correctness, but no verification techniques exist for proving that an emulated system preserves the original systemās functional and timing properties. Here we show how this can be done by combining concepts previously used for reasoning about real-time program compilation, coupled with an understanding of the new and old software architectures. In particular, we show how both the old and new systems can be given a common semantics, thus allowing their behaviours to be compared directly
A Benes Based NoC Switching Architecture for Mixed Criticality Embedded Systems
Multi-core, Mixed Criticality Embedded (MCE) real-time systems require high
timing precision and predictability to guarantee there will be no interference
between tasks. These guarantees are necessary in application areas such as
avionics and automotive, where task interference or missed deadlines could be
catastrophic, and safety requirements are strict. In modern multi-core systems,
the interconnect becomes a potential point of uncertainty, introducing major
challenges in proving behaviour is always within specified constraints,
limiting the means of growing system performance to add more tasks, or provide
more computational resources to existing tasks.
We present MCENoC, a Network-on-Chip (NoC) switching architecture that
provides innovations to overcome this with predictable, formally verifiable
timing behaviour that is consistent across the whole NoC. We show how the
fundamental properties of Benes networks benefit MCE applications and meet our
architecture requirements. Using SystemVerilog Assertions (SVA), formal
properties are defined that aid the refinement of the specification of the
design as well as enabling the implementation to be exhaustively formally
verified. We demonstrate the performance of the design in terms of size,
throughput and predictability, and discuss the application level considerations
needed to exploit this architecture
An analysis of the requirements traceability problem
In this paper1, we investigate and discuss the underlying nature
of the requirements traceability problem. Our work is based on
empirical studies, involving over 100 practitioners, and an
evaluation of current support. We introduce the distinction
between pre-requirements specification (pre-RS) traceability
and post-requirements specification (post-RS) traceability, to
demonstrate why an all-encompassing solution to the problem is
unlikely, and to provide a framework through which to
understand its multifaceted nature. We report how the majority
of the problems attributed to poor requirements traceability are
due to inadequate pre-RS traceability and show the fundamental
need for improvements here. In the remainder of the paper, we
present an analysis of the main barriers confronting such
improvements in practice, identify relevant areas in which
advances have been (or can be) made, and make
recommendations for research
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